We have generalized the Natural Bond Orbital algorithm to handle systems characterized by periodic symmetry. While the code only requires information that can be obtained from the output of any periodic electronic structure calculation, it requires specifically formatted input files. We have created interfaces for the VASP and CRYSTAL software packages, which process those codes' output into the requisite format.
The source code is freely available for download. The code is written in Fortran 90, and requires the BLAS and LAPACK MKL libraries, as well as libraries used in the OpenMP parallelization. Included in each tar download is the necessary source code, make files and a short manual. Additionally each of the interface packages includes a handful of sample systems to run.
We request that anyone who downloads and utilizes the code cite, Dunnington, B. D.; Schmidt, J. R. J. Chem. Theory Comput., 2012, 8, 1902–1911.
DOWNLOAD PERIODIC NBO CODE
(Updated 4/13/15: Expanded manual; Config file for calculation control; Built in visualization)
The NBO algorithm requires the wavefunction to be represented in an atom centered basis. Since VASP expands the density in a planewave basis, we use a projection to interface between the two. A separate patch is included for both VASP 4 and 5.
DOWNLOAD VASP PROJECTION CODE
(Updated 8/28/15: Patch for VASP 5.4 included)
Since CRYSTAL expands the density in an atomic orbital basis set, all that is necessary is to convert the output into a format readable by the periodic NBO code.
DOWNLOAD CRYSTAL INTERFACE